use strict;

my @data = qw/a mnk ab m b bc abcd cd bcd bd m nk/;
@data = sort {length($b) <=> length($a)} @data;

my @result = ();
while (@data) {
    push @result, $data[0];
    @data = grep { $data[0] !~ /\Q$_\E/  } @data;
}

print "@result\n";

[download]
Update
Changed to reflect ikegami's commets.
Please explain the /\Q...\E/
I'm not so sure about the /../i. The OP may want it to be case sensitive.
Thanks.

Update2:
mpeters,
Having read your post and jenda's above, I've incorporated 'index'. Your solution, as it stands, will not work because index returns a position on match and the grep expression needs to return false. So I did it this way. 
...
while (@data) {
    push @result, $data[0];
    @data = grep { index($data[0], $_) == -1 } @data;
}
...

[download]

In reply to Re: Seeking the longest string in an array by nedals
in thread Seeking the longest string in an array by johnnywang

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